What does the word ‘perfidious’ mean?

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Increase your vocabulary and you’ll make your writing much more precise. That’s why I provide a word of the week. Today’s word: perfidious….

I confess there are words I’ve heard multiple times and I still don’t know exactly what they mean.

Back in the days when I had to use a paper dictionary, perhaps I had the excuse of not always having such a volume at hand. But now, with dictionaries chock-a-block on the internet, and my phone never far from my side, what excuse do I have for not looking them up?


That is why, this week, I finally looked up the word perfidious.

I had recently encountered it in the book Days of Abandonment by Elena Ferrante. (Written nine years before before the start of her much more famous Neopolitan Novels, which I have not read, this book displays some early skill and talent.)

Here is how Ferrante used the word:

The poverella was suffering, torn to pieces by the absence of the sweaty red-haired man, and his perfidious green eyes.

I know from context that peridious means something bad or distasteful, but exactly what, I had no idea.

It turns out, the adjective perfidious refers to someone who behaves in a deliberately faithless, treacherous, or deceitful manner (and it appears to describe the man in the photo at the top of this post).

In short: someone who is perfidious cannot be trusted. The term originates from the Middle French word perfidie, which, in turn comes from the Latin perfidus “faithless,” with per meaning “through,” and fidem meaning “faith.”

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